If you're lucky enough to be granted entry to the world of private plane travel, think of it as an invitation to your host's home in the sky. A little jetiquette goes far beyond not sticking your gum under the seat.
It doesn't take much more than a dollop of common sense to know that porn on planes is wrong. It's not just the possible accidental exposure to children that makes it ill-advised. There's really nobody who needs to see anyone else's private Idaho.